The present invention relates to an environmentally safe, moisture resistant, water based construction adhesive and to a method for binding two substrates together using said construction adhesive.
The construction industry relies heavily on high performance adhesives to bind structural components together such as plywood and lumber, gypsum and wood, and styro-foam and wood. High performance construction adhesives are often based on urethane and solvent containing systems. These systems have several problems associated with them. Specifically, the solvent based systems are not environmentally friendly and the urethane based systems contain isocyanate wherein toxicology issues may arise. However, solvent based and urethane based systems provide the superior moisture resistance necessary to prevent construction surfaces from coming apart under severe weather conditions.
The art has attempted to replace the solvent based systems with more environmentally friendly adhesives. Specifically, U.S. Pat. No. 5,534,310 (Rohm and Haas) discloses a latex binder suitable for producing a durable adherent coating comprising (1) an aqueous evaporable carrier having dispersed therein and (2) a latex polymer prepared by mixing, for example, butyl acrylate, methyl methacrylate, ureidomethacrylate, acrylamide, and acrylic acid, chain transfer agent and ammonium carbonate. Said latex polymer has an acid number of 1 to 70 and a low molecular weight in the range of 10,000 to 10 200,000 g/mole. U.S. Pat. No. 5,202,375 (Rohm and Haas) discloses a water resistant polymeric emulsion containing a surfactant (nonionic or anionic) blended with acrylic acid, butyl acrylate, methylmethacrylate and ureidomethacrylate and a cross-linking monomer. U.S. Pat. No. 5,118,749 (Union Oil of California) discloses an acrylic emulsion useful in preparing paints containing acrylic acid, methymethacrylate, butyl acrylate, acrylamide and ureidomethacrylate and a chain transfer agent.
The Applicant""s invention relates to an aqueous based construction adhesive which exhibits moisture resistance performance matching or exceeding conventional solvent and urethane based systems.
Accordingly the present invention relates to a method for adhering 2 substrates together using a composition including
(c) 10 to 95% soft acrylic ester monomers;
(b) 0 to 70% hard monomers;
(c) 0 to 5% of one or more ureido containing monomers;
(c) 0 to 5% vinyl based monomers; and
(e) 0 to 10% polymerizable functional acids
All percentages are weight percent unless otherwise indicated.